Ireland: Kerry - Dublin - Cork - Waterford - Roscommon - Galway - Belfast
UK: London - Manchester - Newcastle - Cardiff - Liverpool
Antithamnionella ternifolia
Invasive Species Information
What Is Antithamnionella ternifolia?
Habitat: Aquatic, marine
Distribution in Ireland: West Ireland coastal areas
Status: Established
Family name: Ceramiaceae
Common name/s: Antithamnionella sarniensis Lyle, red seaweed.
Reproduction: The species has a rapid growth rate and grows abundantly on all types of substrata including eelgrass leaves, algae, animals, pebbles and artificial materials, over a wide range of conditions.
This species shows a wide temperature tolerance. Sexual reproduction is rare with the main method of reproduction being fragmentation.
Antithamnionella ternifolia
Thallus of uncorticated, monosiphonous, prostrate axes bearing erect branches.
Cells with 1-4 determinate branchlets, inconsistent in number per cell and in branching pattern of branchlet.
Gland cells lateral and sessile on 2nd-5th cell of branchlet axis or on branches of the branchlet.
Recent studies on ecology, morphology and reproduction have established Antithamnionella sarniensis and Antithamnionella spirographidis as distinct species.
Genetic isolation also demonstrated by complete failure of interspecific crossing.
Antithamnionella ternifolia
Procarps, 1-3, borne near branch apices on basal cells of successive branchlets usually reduced to one cell beyond the basal (supporting) cell.
Antithamniella has sometimes been included in the genus Antithamnion, but differs in features of branching, position of gland cells, fewer procarps borne on reduced branchlets and tetrahedral division of tetrasporangia.
It has spread fairly rapidly around the coasts in western Ireland . It spreads mainly through remote dispersal as it grows on ropes and ships' hulls.
How To Identify Antithamnionella ternifolia?
Thallus:
Frond: Red Colour
Holdfast:
Antithamnionella ternifolia ID Guide
Antithamnionella ternifolia
Antithamnionella ternifolia
Why Is Antithamnionella ternifolia A Problem?
Antithamnionella ternifolia is an alien (non-native) invasive marine plant, meaning it out-competes crowds-out and displaces beneficial native marine species that have been naturally growing in Irish coastal waters for centuries.
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Displacement of native species
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Introduction of new pests and parasites which affect native species
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Habitat alteration
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Changes in food webs, particularly through dietary competition and predation
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Degradation of integrity of gene pool through hybridisation
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Associated effect of commercial harvesting Improved water quality
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Fouling of ships, marinas, moorings, nets, shellfish & aquaculture structures
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Competition with and predation on aquaculture sp. Food source to humans and wildlife
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Damage to nets
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Increased productivity of previously uncolonised habitats
European Communities (Birds and Natural Habitats) Regulations 2011 non-native invasive plant species A-Z (Updated 2017)
There are currently 35 invasive plant species listed in the European Communities (Birds and Natural Habitats) Regulations (annex 2, Part 1)...
Click on a species from the following list to find out more regarding non-native species subject to restrictions under Regulations 49 and 50.
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American Skunk-Cabbage - Lysichiton americanus
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Brazilian Giant-Rhubarb - Gunnera manicata
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Broad-Leaved Rush - Juncus planifolius
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Cape Pondweed - Aponogeton distachyos
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Cord-Grasses - Spartina (all species and hybrids)
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Curly Waterweed - Lagarosiphon major
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Dwarf Eel-Grass - Zostera japonica
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Fanwort - Cabomba caroliniana
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Floating Pennywort - Hydrocotyle ranunculoides
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Fringed Water-Lily - Nymphoides peltata
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Giant Hogweed - Heracleum mantegazzianum
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Giant Knotweed - Fallopia sachalinensis
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Giant-Rhubarb - Gunnera tinctoria
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Giant Salvinia - Salvinia molesta
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Himalayan Balsam - Impatiens glandulifera
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Himalayan Knotweed - Persicaria wallichii
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Hottentot-Fig - Carpobrotus edulis
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Japanese Knotweed - Fallopia japonica
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Large-Flowered Waterweed - Egeria densa
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Mile-a-Minute Weed - Persicaria perfoliata
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New Zealand Pigmyweed - Crassula helmsii
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Parrots Feather - Myriophyllum aquaticum
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Red Alga - Grateloupia doryphora
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Rhododendron - Rhododendron ponticum
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Salmonberry - Rubus spectabilis
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Sea-Buckthorn - Hippophae rhamnoides
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Spanish Bluebell - Hyacinthoides hispanica
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Three-Cornered Leek - Allium triquetrum
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Wakame - Undaria pinnatifida
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Water Chestnut - Trapa natans
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Water Fern - Azolla filiculoides
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Water Lettuce - Pistia stratiotes
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Water-Primrose - Ludwigia (all species)
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Waterweeds - Elodea (all species)
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Wireweed - Sargassum muticum
Additional Non-Native Plant Species identified as Medium Risk on Ireland's Biodiversity List...
Common name
Barberry
Brazilian waterweed
Butterfly-bush
Canadian-fleabane
Clover broomrape
False acacia
Garden lupin
Giant rhubarb
Hairy rocket
Himalayan honeysuckle
Himalayan knotweed
Holm oak
Pampas grass
Pitcherplant
Red oak
Rock cotoneaster
Salmonberry
Sycamore
Three-cornered garlic
Traveler's-joy
Species name
Lysichiton americanus
Antithamnionella ternifolia
Ribes nigrum
Egeria densa
Buddleja davidii
Conyza canadensis
Codium fragile ssp. tomentosoides
Pseudotsuga menziesii
Solidago gigantea
Gunnera manicata
Persicaria wallichii
Lonicera japonica
Euphorbia esula
Acaena ovalifolia
Matteuccia struthiopteris
Sarracenia purpurea
Bunias orientalis
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